$ git clone -n https://src.fedoraproject.org/rpms/python3.6.git /var/lib/mock/f39-build-1944110-43191/root/chroot_tmpdir/scmroot/python3.6
Cloning into '/var/lib/mock/f39-build-1944110-43191/root/chroot_tmpdir/scmroot/python3.6'...
$ git fetch origin 61a82b989bd275222894c2ad5f1d77e697cf0da1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/python3.6
 * [new ref]         61a82b989bd275222894c2ad5f1d77e697cf0da1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 61a82b9 Remove extra distro-applied CFLAGS passed to user-built C extensions